Getting Started with Rust Plugins

This guide shows the smallest useful Rust reader plugin: it registers a file format, describes its capabilities, and creates a simple drawing when LinkCAD imports a file.

Crate Setup

A LinkCAD Rust plugin is a native library. In a LinkCAD plugin workspace, configure the plugin crate as a cdylib and depend on the LinkCAD plugin crates supplied by the SDK or source tree:

[lib]
crate-type = ["cdylib", "rlib"]

[dependencies]
lc-plugin = { path = "../lc-plugin" }
lc-types = { path = "../lc-types" }

Use the dependency paths or package references that match your SDK layout.

Minimal Reader

use lc_plugin::builder::DrawingBuilder;
use lc_plugin::format::{Format, FormatAttributes, FormatDescriptor};
use lc_plugin::{EndCap, Reader};
use lc_types::Point;

#[derive(Default)]
struct ExampleReader;

impl FormatDescriptor for ExampleReader {
    fn describe_format(&self, fmt: &mut Format) {
        fmt.set_attributes(FormatAttributes::LAYER_NAMES | FormatAttributes::CELL_NAMES);
        fmt.set_file_name_extension("exa");
    }
}

impl Reader for ExampleReader {
    fn parse_file(
        &mut self,
        _path: &str,
        builder: &mut DrawingBuilder,
        _file_size: i64,
        _current_file: i32,
        _file_count: i32,
    ) -> bool {
        builder.set_drawing_name("Example import");
        builder.open_cell_by_name("TOP", true, false);
        builder.select_layer_by_name("L1");

        builder.create_rectangle(Point::new(0, 0), Point::new(1000, 1000));
        builder.create_polyline(
            25,
            &[Point::new(0, 0), Point::new(1000, 1000)],
            false,
            EndCap::Round,
        );

        builder.close_cell();
        true
    }
}

lc_plugin::register_reader! {
    name: "Example Rust Reader",
    extensions: "*.exa",
    license: 0,
    create: || Box::new(ExampleReader::default()),
}

Error Handling

Return false when import or export cannot continue. Log messages through the controller’s event log so users see actionable diagnostics in LinkCAD:

builder.log().error("Could not read the example file header");
return false;

Keep plugin code panic-free at the host boundary. The lc-plugin wrappers are designed for explicit return values and logged diagnostics.

Build and Load

1. Build the plugin for the same platform and architecture as LinkCAD.
2. Copy the resulting dynamic library (.dll on Windows, .so on Linux) into a LinkCAD plugin directory.
3. Restart LinkCAD and import a file whose extension matches the registered extensions pattern.

For export support, implement the Writer trait and register it with lc_plugin::register_writer! or use lc_plugin::register_format! for a combined reader/writer plugin.